Yard::Markdown

Yard plugin to output markdown documentation.

Motivation

Markdown has become the de-facto documentation standard. I heavily rely on Obsidian to render my storage of markdown notes. But markdown is used not just for scribbles, supported is far and wide. We can render markdown file on any device, probably even on thermometer with a screen. But also everyone knows enough markdown to be dangerous (or productive). It's a pitty that rdoc and yard can't output a proper markdown file. I would like to change that.

Goals:

• Compatible with Github Flavored Markdown
• Produce .csv index file
• Mimick yard html layout where it makes sense to maintain familiarity

Usage

Install a plugin

gem install yard-markdown

Run yardoc --format=markdown to generate markdown documentation.

Markdown files in the project tree are detected automatically, copied unchanged into the output, and listed in index.csv:

yardoc --format=markdown

Markdown files whose basename starts with _ are ignored automatically.

Use YARD's --exclude option to omit a separate documentation tree:

yardoc --format=markdown --exclude '\Adocs/'

FAQ

Note on RDoc support

It seems important to note, that yard claims to have support for RDoc. That support is certainly present, but output for rdoc is dramatically different. A lot of useful information seems lost in the process.

If you know how to improve that, please get in touch or submit a patch.

So in meantime, there is work going on a competing gem for RDoc and it's called rdoc-markdown gem.

Note on index.csv file

This gem emits index of all markdown files in a index.csv file.

There are decent tools that offer search through structured plain-text files. But my expectation is that nobody will use CSV as an actual search index, but rather import it into something that performs this function better.

In my personal use-case, I use SQLite. All other databases seem to have a good support for CSV imports.

Yard doesn't load plugin properly?

so you need to load plugin through ~/.yard/config:

load_plugins: true
autoload_plugins:
  - markdown

Testing

Unit tests verify renderer behavior, index links, and anchor consistency for both YARD-style and RDoc-style sources.

Run:

bundle exec rake test

Regenerate local sample docs:

bundle exec rake examples:generate

Validate generated markdown in sample docs:

bundle exec rake markdown:validate_examples

There is also a real-world validation harness for repositories with substantial YARD documentation (faraday, sidekiq):

bundle exec rake markdown:validate_real_world

This task validates every generated Markdown file against CommonMark and GFM. Generated files must have valid local links and anchors; unresolved links and anchors in byte-identical Markdown copied from upstream are reported instead of failing validation.

GitHub Actions CI runs this task on every push/PR, so both real-world fixture gems are verified continuously.

For reproducible checks, the task clones pinned tags (faraday v2.14.3, sidekiq v7.3.10) into tmp/real-world/repos and honors each repository's .yardopts before generating output in tmp/real-world/faraday and tmp/real-world/sidekiq.